This request is intended to ask to the BOUML tool developers to make the needed changes that allow to put the name of the connector lines in several text lines and no only in one text line. Please, take a look of the image I send attached to this email and pay special attention on the text in red. I hope it helps to explains better what I mean.

I will allow to specify a max width (in characters) for (at least) the name of the flows like I did for the name of the use cases.

To show the input/output parameters just draw the activity in the diagram moving it by drag&drop and choose "draw activity" (rather than "add a call behavior"), the activity's parameters will be automatically drawn. Example (from screenshots) :

Let's note I recommend to draw first the activity in the diagram and to probably increase its size, because all its sub elements must be drawn inside the rectangle representing the activity.

P.S. you speak about developers, since the beginning I am working alone on Bouml